Many parts of the world have inadequate rainfall at different times of the year sufficient to sustain non-native vegetation, such as lawns, playing fields, golf course, flowers, shrubs and other ground cover. Irrigation systems have been extensively developed that include a plurality of sprinklers connected to pressurized water supply lines and solenoid actuated valves. An electronic controller automatically turns the valves ON and OFF in accordance with the run and cycle times of a watering program to provide vegetation in different zones of the sprinkler system with the desired amount of precipitation. A wide variety of sprinklers have been developed for use in such systems, including drip, bubbler, impact drive, spray, rotary stream, and rotor type sprinklers.
Spray type sprinklers are well known in the irrigation art and typically include a spray nozzle that is screwed to the upper end of a fixed vertical riser or a telescoping vertical riser in the case of a so-called pop-up sprinkler. The spray nozzle is usually a generally cylindrical construction made of plastic parts. Typically a fixed orifice distributes water radially in a relatively thin fan-shaped pattern to close-in vegetation, e.g. turf and shrubs located seventeen feet or less from the spray nozzle. The circumferential size of the fixed orifice is chosen to provide, for example, one-quarter, one-half and full circle arc of coverage. The size of the fixed orifice can also be selected to deliver a particular flow rate in terms of gallons per minute, although arc size largely determines flow rate. Usually the fixed orifice is sized and configured to provide matched rates of precipitation over a given sector size. For example, a one-quarter circle arc spray nozzle will typically deliver water at half the rate of a one-half circle arc spray nozzle of the same design.
Conventional spray nozzles often include a small throttling screw that can be turned with a screwdriver from the top side to adjust the flow rate of the sprinkler, which can also adjust the reach or radius to some degree. Examples of irrigation spray nozzles are disclosed in U.S. Pat. Nos. 4,189,099; 4,220,283; 4,739,934; 5,642,861; 6,158,675; and 6,957,782. Some spray type sprinklers include an internal pressure regulator as disclosed in U.S. Pat. No. 5,779,148 for example. Some spray type sprinklers include an internal debris strainer or screen as disclosed in U.S. Pat. No. 4,913,352.
U.S. Pat. No. 4,579,285 granted Apr. 1, 1986 to Edwin J. Hunter and entitled ADJUSTABLE SPRINKLER SYSTEM discloses an irrigation spray nozzle with an adjustable arc spray orifice that can be adjusted from about zero degrees to three hundred and sixty degrees. One of two opposing spiral peripheral lips can be rotated relative to the other by twisting a top screw to change the circumferential length of the nozzle orifice formed between the two lips. The height of the upper lip relative to the lower lip can also be adjusted with the same screw by holding the upper lip stationary and twisting the screw in order to change the vertical height of the nozzle orifice. Ed Hunter's '285 patented spray nozzle alleviated the necessity of manufacturing spray nozzles with different fixed spray patterns and it therefore has enjoyed, and continues to enjoy, widespread commercial success.
Hardscapes, such as concrete sidewalks, can absorb substantial solar energy and radiate heat to adjacent landscape, such as lawns watered with spray heads. Portions of the lawn immediately adjacent these hardscapes watered with conventional spray heads can to turn brown from inadequate watering even where the remainder of the lawn is watered sufficiently to keep it healthy and green.